Gas mask canisters



March 4, 1958 w. E. ,GROSS GAS MASK CANIsTERs Filed Deo. 22. 195o 2 Sheets-Sheet l INVENTOR.

WILLIAM E. GRSS BY l// ATI'DRN EY 'March 4,1958 w, E @R055 2,825,424

GAS MASK CANISTERS Filed Dec. 22, 1950 2 Sheets-Sheet 2 Fj/g. 2.

o o u o n n u w* n n n n n n an i INVENTol-z.

BY WILLIAM EGROSS ATTEIFINEY United States aten GASfMASK CANISTERS William E. Gross, Joppa, Md., assigner to the United States of' America. as represented by the Secretary of the Army, as trustee Application December.22,.1950, Serial No. $32,282 2 Claims.v (Cl..1834.3)

(Granted'under'l'itle', U. S. Code (1952),.sec. 266) The invention described herein may be manufactured and'used by or for the Government for governmental purposes,- without` the payment to me of any` royalty thereon.

This invention relates` generally to air purification and filtering` equipment and'particularly to apparatus for removing'noxious and deleterious` gases, fumes, vapors and the-like from contaminated air.

In order'to purify' air and render itfit for breathing, itf-is currently the practice to use a gas mask having a canisterV associated therewith. In this arrangement,.con taminated air must pass through the canister. where it is purified' and' tiltered before' itis inhaled.

The canisters currently used; ordinarily comprise a container which houses. an erosol lter and a sorbent. The sorbent is ordinarily' a powdered' or granular materi'alisuch as powdered' or granular charcoal and' is. separatedffrom' the` aerosol filter by' a perforated plate and a` lilter pad. When the canister is subjected to rough handling, 'the perforated plate is sometimes displaced or deformed. In the former instance, canister failure results, and inthe latter .instance the canistersf electiveness is impaired' because channeling of gasesresults. Another delieiency in the currentlyusedz canister is that' the filter pad, which is madeof albrousmaterial, frequently clogs up perforations i'n the embossed perforated plate. This causes the airto' by-pass the'clogge'd-up perforations and resnltsin ineliicient purication of the air; due tothe fact thatl there .lacks Vuniform contact of. the air: with. the sorbent; Avery serious deficiency of the currently used canisters is.' that the aforementioned iilter pad, during storage, isv often forced down into theV valleys between the'. emboss-rnents of the perforated' plate/by the: pressure of the sorbent filling. This increases the volume of the sorbent compartment which in turn permits loosening of the sorbent with consequent channeling by gases.

It is a specific object of this invention to provide a durable, lightweight, efficient canister which is adapted to be associated with a gas mask, and in which the dehciencies present in the currently used canisters are eliminated.

Another specific object of this invention is to provide a canister of rugged design and construction which will not be deformed when subjected to rough treatment or long periods of storage, thereby avoiding channeling of gases which results when a canister is deformed.

Other objects and advantages will become more apparent from the specification and drawings.

In the drawings, wherein like reference characters indicate corresponding parts throughout the several views;

Fig. l is a vertical section of the upper half of a gas mask canister embodying the features of the invention.

Fig. 2 is a plan view of the sorbent retainer assembly with the four disks separated and placed in overlapping relationship with each other to show the structure of the disks in detail.

Referring to the drawings, there is shown in Fig. l, a

2. portion of. an axial iiow canister designed so that it can be attached directlyv to theY facepiece of a. gas mask in either the chee Y or fsnout positions' or atY any other desired point. TheV canisterv comprises acylindrical casing 1 having an' outlet Wall 2 at one end. that terminates in an axially extending nozzlefr, and: at; the other. end of the casing 1 thereis-.secured thereto, the canistenbottom; The canister bottom is: cup-shapedzand includes the bota tom portion 5- having am air inlet. opening 6 therein for-med' by inwardlyl extending:Y portion.` 7,. landA an. axially extending bange: 8: at its outerperipheral edge which.: is secured to the casing 1 at 9. The ange. 8- im crimped' over the annular rib-10 which is `formedzin the; casing 1 by swaging. Rubber compression seal 11. is positioned at the joint between thecasing I. and the: ange 8A of'the canister bottom, and renders; the joint. air tight; An aerosol filter retainer 12 whichv is embossed, pere forated' platea, is positioned: within the caniserf bottom-4 and fits snugly within the ange'S. llhe central portion 13 of theV aerosol filter retainer 12 isY spaced from. the canister bottom Lt` and. supported by the cylindricalzsupportI 14, which isv positioned' between the aerosol filter retainer 12 and theinwardly extending portion: 7 of the canister bottom. 41. The support prevents the canister bottom 4 from being forcedY against. the: aerosoli filter retainer 12. It the canister bottomv 4lwas forced yagainst the aerosol tilter retainer, the chamber between them would bel constricted. and this. would create. a high resistance to breathingr The conventional aerosol filter 15, which; is a pleated sheetof fibrous filter material, is positioned between thea aerosolfilter` retainer; 12 and Vthe sorbentv retainer vassembly 16, which will'. subsequently beY described in greater detailt. The sorbent retainer as.- sernbly.- 16 is. positioned in casing.` 1a by inwardly.A directed rib 1-7.. The aerosollter is heldf in position withinztlre end of casing 11 by the'cl'arnp; wedge ring 18'. The; casing 1 has an annular rib 19 formed therein byswagi'ng'whiclr forms. an internat annular channel designated as' 20. sorbent retainer assembly 2'1, .whichiis` identical tosorbent retainer. assembly 16v is positioned. inl channel. 20. A sorbent 222v such as, granulatedv or powdered charcoal or: the likev is, tightly packedfinf the: chamber defined: by` the casing 1 and the-twosorbent. retainer assemblies.. The central portion 23 of the sorbent retainer assembly 21 is snpported'by the cylindrical support member 24. which is positionedbetweenthe'nozzle 3.- and the embossefplate 36 which is one of the parts of the sorbent retainer assembly 21.

Closure cap 26 is mounted on the nozzle 3 with gasket 27 positioned therebetween to effectively seal the outlet opening. The closure cap 26 prevents the entrance of moisture into the nozzle 3 when the canister is not in use. Similarly, closure plug 28, which is removably mounted in adapter 29, seals off the air inlet opening 6 from entrance of moisture when the canister is not in use. Gasket 35 seals the joint between the adapter 29 and the portion 7 of the canister bottom 4.

Following is a detailed description of the sorbent retainer assembly, which is a salient feature of my invention. Each sorbent retainer assembly comprises the following: an embossed, apertured plate 31) made of a light, strong metal which has an axially extending ange 31 at its outer peripheral edge, a thin perforated metal plate 32, a disk 33 of woven wire screen which may be a plastic material, and a fines retainer 34 which is a pad of filter material such as filter paper. As shown in the drawings, the perforations in embossed plate 30 are considerably larger than those in thin metal sheet 32. When the sorbent retainer assembly is in its operative position, the three last-named members are positioned parallel and adjacent to the embossed plate and within said bange,

withi said ang'e crimped over said members, thereby satisfiesV Y forming a self-contained assembly. YThe sorbentretainer Y assembly functions as follows: the embossed, aperturcd; L plate forms a rigid wall ofY the sorbent chamber-1 but 'v allows airto'pass through; adjacentYtoYthis plateV is Vposi-W tioned the vthin perforated plate which allowsV air toY pass through its perforations but prevents thermes` retainer from being forced Vdown Yinto Vthe valleys between Ythe embossnients Vin the apertured plate,Y preventingrclogging of the apertures, and increase inthe volume of the sorbent compartment; the disk `of woven wire screen spaces Y the iinesretainer from the perforatedplate, preventing it,V from clogging the perforated plate,Yand generally irn- Vproving the ow'of the air;,the ines retainer primarily prevents theescape of any of the sorbent from the sor- VYbent chamber. t t 'Y Y The operation Vof the canister is as'followsfzcontami- V4natedqair enters the inletA end opening andfpasses through theV aerosol lter retainer 12,- the aerosolvlter 15,'the. sorbent retainerY assemblyY16, thesorbent 22, the sorbent retainer assembly 21, YandYoutYthenozzle 3` which may be; connected Vto the facepiece of a gasrnask.Y

YThe improved canisterYtthat'I have. disclosed has theY following advantagesover prior devices:` (l) The sorbent retainer-,assemblies formj walls of the chamber which'V houses the sorbent, and present stiff, unyieldng'surfaces to the sorbent, Ythereby Ypreventing any increase' in the Y,

volume ofthe sorbentrchamber and the resulting chan-V nelingtofY gases whichroccurs when thresfcanister is Y,sub-

Y jected to rough treatment or to long periods of storage. Y

v(2) The sorbent retainer assembliesVV are securelyY posi-Y r tionedin fthe casingjby swaged ribsthereby preventing displacement or deformation Yof .theassembly'tand the vresulting' canister failure orjlcanister ineiiiciency.. YY(3) kThe canister bottom is supported in spaced relation to Y the aerosolV filter retainer by the cylindrical support, thereby preventing theY canister bottom Vfrom being forced Y agrainstfthe aerosolv lter retainer andthe resulting -con.

strictionof theair channel between the'canister bottom andthe aerosol lter retainer which causesy increased resistance tobreathing. 's Y From thefo're'going description, the construction and operation. of the device, and its advantages will be readi-gY ly understood by those skilled inthe'art: MinorY changes Y Vin theVV details ofi construction illustrated and described maybe made withoutV departingrfrom the spiritvof theV invention, as deiined by the appended claimsf Y l. AV gas mask canister comprising a casing' having a Y cylindrical side wall and a frustoconical outlet endY wall Yterminating in -a central outlet 'connectionQaf-rst disk-f Y' shapedl sorbentY retainer assembly extending'across said housing substantially at the junction ofYsaid frustoconical outlet end wall and said cylindrical side wall, a second disk shaped sorbentV retainer assembly extending across said casing at aYpointV spacedfrom Ysaid rstlassembl'yga Ymass of finely' divided sorbent material substantially Y llingthe space between, saidY assemblies, eachYof said the peripheries ofthe other members'of saidassembly,

said cylindrical wall being Ydeformedrabout said crimped Y 'periphery of each of said embossedV platesand holding n Ysaid assemblies in position in'said casing, a cup shaped t Vcanisterbottom. having a Vcylindrical ange'portion interi Y i Yfitting with said casing, a'frus'toco'nical end `wallV having an 'Y air inlet openingY centrally thereofQa perforated plateY extending across said canister bottomY adjacent the" nter-Y assembliestconiprising a sheet Yof fibrous lte'r'imaterial adjacent saidtniass ofrsorbent material, aY sheet pofswoven Ywire screen adjacent said filter materiaLa thin' perforated metal sheet adjacent said woven -wire Vscreerl,a1:id`a rigid t i iem'oossed sheet o'metal having/perforationsconsiderf Y YY Y ably larger than `the perforations of said thin'metal sheet with the bosses holding the perforated portions` ofr'lsaid t embossed sheet away from said thinY 'metal` sheet, the

periphery of said V.embossedjsheet Vbeing crimped about section of said cylindrical' ange and v an; aerosol tilter formedof pleated lbrous sheet/material extendingV be-YV Y tween s and engagingtsaid ,second retainerV 'assembly and Said lastnamedperforatedplatef.. .t l `Y '2. AY canister Yas .defined in ,claim n n* prisingY a iirst Y'supp'ort rigidly mounted onV said frusto` `,ReferencesCited Vthe iile of this patent A' YT YYY Y UNiTED STATESV PA'rEN'rsi Y Stelzner' Y Y Y1,789,262 Y Monro et a Jan."1'3, 1931; `1,963,874 Y Stanilip l111e'.19,` V1934 2,008,677 Booharm July 23,- 1935 2,104,016 Biggs ]an.'"4,' 1938'` t Nov. 11Y,l19'30' l Schwan; Y Mat-:22,-193s` Y 

